Docs: Workflow example for GitHub Action

[ocean90]

Idea:
For PRs, detect coding standard violations via PHP_CodeSniffer. Errors should prevent the PR from being merged and shown to the user.

Implementation:

• A GitHub Action to set up PHP with Composer and to run phpcs
• To prevent the branch from being merged, use protected branches with phpcs as a required status check.
• Display errors via PR annotations in Checks via cs2pr

Result:

name: PHP_CodeSniffer

on: pull_request

jobs:
  phpcs:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v2

      - name: Setup PHP
        uses: shivammathur/setup-php@v2
        with:
          php-version: '7.3'
          coverage: none
          tools: composer, cs2pr

      - name: Get Composer cache directory
        id: composer-cache
        run: |
          echo "::set-output name=dir::$(composer config cache-files-dir)"

      - name: Setup cache
        uses: pat-s/always-upload-cache@v1.1.4
        with:
          path: ${{ steps.composer-cache.outputs.dir }}
          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
          restore-keys: |
            ${{ runner.os }}-composer-

      - name: Install dependencies
        run: composer install --prefer-dist --no-suggest --no-progress

      - name: Detect coding standard violations
        run: vendor/bin/phpcs -nq --report=checkstyle | cs2pr

Limits:

• Only 10 warning annotations and 10 error annotations per step (source)

[ocean90]

Related blog post: https://dominikschilling.de/schnipsel/github-action-workflow-php-codesniffer-check-annotations/

[grappler]

I really like the GitHub Action though I think it is not necessary to give feedback on files that have not been changed like so:

By only checking the modified files it could slightly help with the annotation limit.

We could use the File Changes Action to only check the modified files.

[ocean90]

Moved to https://handbook.required.com/development/coding-standards/continuous-integration-ci/#github-workflow.